In recent years, compounds having serotonin 5-HT.sub.3 receptor antagonism have been studied extensively and some of them are now used in the clinical field, because of their function to repress nausea and emesis as side effects caused by the use of carcinostatic agents such as cisplatin and the like or by radiotherapy. However, as is evident in benzamide base drugs, these prior art compounds are not always satisfactory in view of their drug effects free from side effects.